Vibrant bar and method of tuning the same



Feb. 17, 1942. H. J. SCHLUTER VIBRANT BAR AND METHOD OF TUNING THE SAMEFiled April 24, 1959 Patented Feb. 17, 1942 VIBRANT BAR AND METHOD OFTUNING THE SAME Henry J. Schluter, Chicago, 111., assignor to Jack C.Deagan and Ella L. Deagan Application April 24, 1939, Serial No. 269,647

9 Claims.

The present invention relates in general to vibrant bars such asutilized in musical instruments of the percussion type such as bells,chimes, carillons and the like, and is particularly concerned with animproved method of tuning vibrant bars for such instruments so that aperfeet consonance of their tone compounds may be obtained.

Heretofore, in the manufacture of vibrant bars for musical instruments,these bars being either of the solid or tubular type, it has been theusual practice, particularly in bells and chimes, to make the bars fromtubular or solid stock of suitable material and finish these bars so asto have uniform diameter properly proportioned to the length of the barto give the required key note, when the bar is set into vibration.

Moreover, it has been discovered that, even though the material for thebars be selected with the greatest of care, two bars constructed ofseemingly the same material and having the same dimensions will seldomhave the same pitch nor will the partial tones be in consonance with thefundamental key tone of the bar. Such condition results in a largemeasure from differences in the homogeneity of the bar material.

As a consequence of the above, when the usual bar of uniform diameter isbrought to the desired fundamental key tone pitch, the composite musicaltone of the bar is found upon analysis to generally comprise a compoundof dissonant partials manifesting plus and minus differences from theirtrue intervalic relationship in a musical scale of equal temperament.Thus, the chord formed by the key tone and its resulting partial tones,even though the key tone may be of the correct pitch, may in factproduce a composite or compound tone which is clissonant and enharmonic,and which sounds out of tune.

Having in mind the above as well as other objections to vibrant musicalbars as presently constructed, the present invention contemplates as theprimary object the providing of a musical bar of improved constructionin which the partial tones of the bar will have their correct intervalicrelationships to the fundamental key tone of the bar, whereby perfectconsonance of the tone compound will result.

A further object of the herein described invention is to provide animproved process or method for the tuning of vibrant musical bars, suchfor example as bells, chimes and thelike.

Another object of the present invention is to provide a novel processfor tuning vibrant musical bars, which will permit of the partial tonesof the composite bar tone being each treated and tuned as an individualfactor, both as to its specific periodic vibration frequency and itsintervalic relation of key-note consonance.

Still another object of the invention is to provide improved means forthe tuning of musical bars, wherein the bar may be altered mechanicallyto change its composite musical tone to a desired degree.

Still another object of the herein described invention is to provide animproved supporting arrangement for vibrant bars, whereby the mostdesirable tones in the different registers of a musical instrumentutilizing such bars, may be made to predominate.

Other objects of the invention will more fully appear from the followingdetailed description taken in connection with the accompanying drawing,which illustrates the embodiment thereof, and in which:

Figure-1 is a view in elevation illustrating a vibrant bar embodying thefeatures of the herein described invention, and showing the manner inwhich it is suspended to form a chime or bell;

Figure 2 illustrates a musical stafi showing a fundamental key tone andseveral arrangements of associated tuned partial tones comprising theseveral tones of the composite or compound tones of vibrant bars such asembody the features of the present invention, these tones being producedwhen the bars are set into vibration;

Figure 3 is an enlarged fragmentary view of a section of my improvedbar, showing its novel shaping and illustrating the manner in which theindividual tones of the bar may be tuned to bring them into consonance;

figure 4. is an enlarged fragmentary end View of a solid bar showing animproved end construction thereof and the manner in which this bar maybe suspended for use in a musical instrument;

Figures 5 and 6 are similar views illustrating the manner in which myimproved vibrant bar may be suspended to produce different predominatingtones in the diil'erent registers of musical instruments utilizing suchbars.

As shown on the drawing:

Vibrant bars, such as disclosed in Figure 1, constitute bells or chimeswhich may be assembled into a musical instrument such as a carillon orchime which may be arranged for playing in any desired manner, such asby striking the bars with hammers or by providing suitable mechanism sothat they may be played from a keyboard. It is thought that for purposesof illustration, it will be sufficient to describe a single bar, as forexample, a bar having a fundamental pitch tone or key note correspondingin the musical scale to middle C having a vibration frequency of261.625. Such a bell or chime would have a length of substantiallytwelve feet four inches, and would be of suitable diameter to producethe desired fundamental tone.

Vibrant bars for utilization as bells, chimes and the like haveheretofore been constructed to have uniform diameter. It is found,however, that bars so constructed are objectionable in that theircomposite musical tone is a compound of dissonant partials havingimproper intervalic relation to the fundamental key tone which producesa composite or compound tone that sounds out of tune when the bar isstruck or played.

Referring to Figure 2, a bar of this character having uniform diameterwould produce only approximately all the tones shown in either of theexemplary chords on the musical'staff in Figure 2. In other words, thesix major partials of the tone compound, exclusive of the fundamentalkey note, would manifest plus and minus differences in their relation tothe musical scale of equal temperament. Some of the partial tones mightbe sharp and the others might be flat.

In my improved bar, as generally shown at A in Figure 1, the bar isundulated at predeter mined intervals along its length, the positions ofthese undulated portions having a definite relation to the antinodepoints of the bar tones and being so shaped as to result in tuning thebar tones so that they will be in consonance, as will hereafter bedescribed in detail.

In the bar shown in Figure 1, the nodal points of the key tone areindicated at and its antinode points at Illa. The nodal points of thefifth, first hum and eighth partials are respectively shown at l I, I2and I3, and the node points of the sub-hum partial, an octave below thefirst hum partial tone, are shown at M, with their correspondingantinodes shown at Ha, Ha, [3a, and Ila, respectively. The node pointsof the third overtone above the key tone and the sec-- ond octave tonebelow the key tone have not been shown in Figure 1. While these tonesare in evidence in the bar and can be tuned, if desired, they are soobscured in the composite tone as to have only slight effect upon it.

Bars of the herein described type are usually suspended in a verticalposition by means of a its ends anchored on a suitable support as shownat I6.

From a study of the tones comprising the compound tone of the bar, itwill be apparent that the partial tones having the most effect upon thetone qualities of the bar will be the fifth, eighth, first hum and theso-called sub-hum tone partials.

As shown in Figure 3, the central and adjacent central portions of thebar have been illustrated on a large scale. It will be noted from thissection of the bar that node points of the fundamental key note, eighthpartial, and first hum tone partial all fall at the mid point or centerline of the bar, as do also the antinodes of the fifth and first humpartial tones.

In constructing a bar according to my improved method, the bar is firstconstructed with uniform diameter, except that the dimensions of the barare such as to produce a bar in which the different tones are abovethose which are actually desired to be produced in the bar after it istuned. For example, if the tuned bar is to have the fundamental key noteC, the bar would be initially constructed with proper diameter andlength to give it a key tone of approximately C-sharp. During the tuningprocess, the bar is undulated with reference to the antinode points toindividually and collectively vary the difierent tones to bring them tothe desired pitches, as will now be described.

To illustrate my tuning method, as shown in Figures 1 and 3, portions ofthe bar surface have been removed to form circumferentially extendinggroove portions adjacent the antinode points of certain of the partialtones. For example, the grooved portions as shown at [1 and I8 are ingeneral symmetrically positioned with reference to the antinode pointsof the key tone, and the fifth and hum tone partials.

In general, I have discovered that the key tone and its accompanyingpartial tones may be varied as to their respective pitches and bebrought into consonance' or tuned relation by varying the widths anddepths of these grooved portions in the different parts of the bar,depending upon the relative levels of the pitches of the tones, and theamount it is desired to change the pitch of a particular tone inrelation to the others.

If the groove I1 is deepened as indicated at I! this would have its mosteffect upon the adjacent antinode of the key tone and would lower itspitch. Other tones would be slightly changed, but their rate of changewould not be as rapid as that of the key tone. Similarly, deepening ofthe groove l8 will have its greatest effect upon the adjacent antinodesof the fifth and sub-hum tone partials and decrease their pitches atgreater rates than the other tones.

By widening the grooves IT in the directions as shown by the dash lines20 and 2|, the effect will in general be to decrease the pitch of thetones farthest from the key note at a greater rate than those which arecloser to the key note. The widening of the groove at 20 would decreasethe pitch of the eighth partial faster than the fifth and first humpartial tones, and the widening of the groove as shown at 2! would haveits greatest effect upon the sub-hum tone partial and would not affectthe first hum partial to any great extent.

Knowing the effects which may be secured by V removal of material asdescribed above, it will be mounted.

be readily apparent that by successive checking of the tones of the barand the removal of the material in the proper portions of the bar, thebar tones may be tuned and brought into consonance with the fundamentalkey tone at the desired pitch.

It has heretofore been the usual practice to simply drill diametricallyextending holes through the upper ends of the bars which were to beincorporated in a carillon or other musical instrument in which the barsare suspended from their uppermost ends, these holes being equallyspaced in all the bars from the bar' ends. It has been found that thismanner of suspending the bars seriously interferes with the tonequalities in the different registers in which the bars might Inpractice, it is desirable in the upper registers of the musicalinstrument to have the fundamental key tone predominate, whereas in thelower registers it is more desirable to have the partial tonespredominate.

Referring now to Figure 4, there is shown an arrangement which I haveutilized in connection with bars of the solid type for producingpredominating tones in the different registers. In this arrangement, thebar in general would be provided with undulated portions as shown inFigure 1. I have found that the tones of solid bars may be generallyimproved by providing a resonator which is tuned to the key note of thebar. This resonator comprises an internal end recess 22 which is of suchdiameter and depth as to effect tuning it to the key note of the bar.The bar, as shown, is supported upon a hanging cord or cable which ispassed through the bar In this arrangement, the key at the key node.tone will predominate. On the other hand, if the hanging cable is passedthrough an adjacent partial node point instead of the key tone node.then that particular partial tone may be made to become morepredominant.

As shown in Figure 5, the bar, in this case a tubular bar, is shown withthe supporting cable l5 passing through the node of the fundamental keynote at this end of the bar as indicated at In. With such suspension,the fundamental key tone would predominate, and this type of suspensionwould be preferably used for one of the upper registers of theinstrument.

As shown in Figure 6, the suspension cableis at the node of the fifthpartial, so that as thus suspended the fifth partial tone wouldpredominate, thus making this type of suspension preferable for thelower registers of the instrument.

From the above description, it is thought that the method or process oftuning vibrant bars according to the principles of my invention, will beclearly understood.

From the foregoing description, it is apparent that the presentinvention provides an improved musical bar in which the partial toneswill have their correct intervalic relationship to the key tone andproduce perfect consonance of the tone compound;'which embodies animproved process or method for the tuning of vibrant musical bars, suchas bells, chimes and the like; which permits of the partial tones of thecomposite bar tone being each treated and tuned as an individual factor,both as to its specific periodic vibration frequency and its intervalicrelation of key-note consonance; which provides improved means for thetuning of musical bars, wherein the bar may be altered mechanicallytochange its composite musical tone to a desired degree; and in which animproved supporting arrangement is provided for vibrant bars, wherebythe tones in the different registers of a musical instrument utilizingsuch bars. may be made to predominate.

It will, of course, be understood that various details of constructionmay be varied through a wide range without departing from the principlesof this invention and it is, therefore, not the purpose to limit thepatent granted hereon otherwise than necessitated by the scope of theappended claims.

I claim as my invention:

1. A percussion musical instrument bar shaped to provide sections ofsubstantially uniform diameter spaced apart longitudinally. of the bar,and sections interconnecting the first sections having surfacesundulated in a direction longitudinally of the bar, said latter sectionsbeing of different lengths and depths.

2. In an elongate round vibrant bar of initially uniform characterhaving a fundamental and a plurality of partial tones initially indiscordant relation, rugosities provided in the bar of such depths andwidths as to bring the fundamental and partial tones of the bar intoconcordance.

3. The method of tuning a round vibrant bar of initially uniform crosssection from end-toend which comprises varying the cross-section of thebar at spaced intervals along its length to relatively change thepitches of the fundamental and partial tones of the bar and bring theminto concordance.

4. The method of tuning an elongate musical bar having a fundamentalnode substantially at its center and a plurality of accompanying partialtones in non-concordant relation, which comprises varying the barsurface on either side of its center to tune the fundamental tone to adesired pitch and tune the partials with respect to each other and tothe resulting pitch of the fundamental.

5. In a musical instrument having a plurality of vibrant bars definingupper and lower registers, and supports for said bars, the supports inthe upper register being positioned with respect to their associatedbars to have points of engagement substantially at the nodal points ofthe fundamental key tones of the bars, and the supports in the lowerregister having points of engagement with their associated barssubstantially at node points of the partial tones.

6. A solid vibrant musical bar having an internal end recess extendingaxially into the bar end to form a resonator tuned to the key tone ofthe bar.

'7. A solid vibrant musical bar having an internal end recess extendingaxially into the bar end to form a tuned resonator, and means forsuspending said bar at a point adjacent said recess. I

8. The method of changing the frequency of key note and partial notes ofa cylindrical bell including the 5th and 8th harmonics and the hum andsubhum partials thereof to tune the same to the key tone which includesproviding formations on the peripheral surface of the cylindrical ballat predetermined points therealong having a different diameter than theinitial diameter of the bell and then further altering th dimensions ofthe peripheral surface of the cylindrical bell at predetermined portionstherealong to bring the partials into exact tune with the key tone ofthe bell.

9. The method of lowering the partial tones of a cylindrical vibrant barincluding the 5th and 8th harmonics and the hum and subhum partialsthereof to tune the same to the key tone of the bar which includesforming a relatively broad shallow groove in the peripheral surface ofthe vibrant bar at predetermined points therealong, including certainpredetermined antinodal points of the key tone and the 8th harmonic, andthen further removing metal at points in proximity to the antinodalpoints of the key tone and partials which are furthest out of tune tobring the partials into exact tune with the key tone.

HENRY J. 'SCHLUTER.

